GRASS BLADES UNDER A MICROSCOPE LOOK LIKE A BUNCH OF HAPPY FACES
One of the most common plants and an essential part of many environments is grass. We all know what it looks like to the unaided eye, but when a cross-section of grass is examined under a microscope, a sequence of happy smiles is revealed. After being uploaded to the internet, this specific picture swiftly gained popularity. There is a lot to say about the science behind this "smiling grass" picture and whether or not all grass, including the one in your backyard or neighbourhood park, looks like this, even if the image is absolutely real and not artificial intelligence.
Phil Gates, a biology professor at Durham University and the creator of The Guardian's Cabinet of Curiosities natural history blog, took the original photo. He accomplished this by applying two dyes to a thin piece of marram grass (Ammophila arenaria) and scanning it with blue-violet light. Gates is credited with saying, "I hope the image stimulates the imagination of kids to take an interest in plant anatomy." The artwork was created in 1984.
“The blue smiles are made of phloem tissue, which carries nutrients around the plant and has pure cellulose cell walls,” explains Chemical & Engineering News. “Chlorophyll-rich cells, which fluoresce brownish-red without any added dyes, can be exposed as the grooves in this sample open up in response to water in the air, uncurling the blades of grass and triggering photosynthesis.”
Naturally, the idea has produced charming visuals, leading many people to believe that the grass is constantly watching and grinning back at us. But the truth is a little more complex than that. Each stalk of grass is made up of vascular bundles, which are essentially tubes arranged vertically. Vascular bundles come in two varieties: phloem, which is narrower and carries nutrients, and xylem, which is wider and carries water. If you can visualise them, the former would be the smiling face's "mouth," and the latter would be its eyes. Alternatively, the entire face may simply be well-positioned xylem.
However, those who have reached out for their microscope to see the smiling grass have most commonly found a surprised face, much like a “:O” emoji. “I saw what looked like faces, but they weren’t smiling. Instead, I saw spooky, ghost-like ‘faces' staring back at me!” writes Foldscope Instruments, a microscope company. “The xylem and phloem bundles just happened to line up to form what looked like eyes and an open mouth.”